Improvement in frofedlers



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Letters Patent No. 90,590, dated May 25, 1869.

IMPROVEMENT IN PROPELLERS.

The Schedule referred to in these Letters Patent and making part of thesame.

To all whom it may concern:

Be it known that I, CHRISTIAN, SHAnrs, of Philadelphia, Pennsylvania,have invented certain Improvements in Propellers, and in vessels for thesame; and I do hereby declare the following to be a full, clear, andexact description of the same.

My invention consists of certain improvements, fully describedhereafter, in the propeller for which Letters Patent were granted toJacob Perkins, November 20, 1829, also of improvements in vessels forsuch pl'opellers.

The main object of my invention is to use a large propeller-wheel on avessel of light draught, and to so adapt the vessel to the wheel as toobtain 'the best effects from the latter.

In order to enable others skilled in the' art to make and apyly myinvention, I will now proceed to describe its construction andoperation, reference being had to the accompanying drawing, which formsa part of this specification, and in which- Figure Il, Drawing N o. 1,is a side view ofthe stern and propeller of the boat.

Figure 2, a plan view.

Figure 3, a vertical section on the diagonal line 1 2, i 2.

gFigure 4, an inverted plan view.' v

Figure 5, a transverse section on the Vline 34, fig. 4.

Figures 6 and 7, Drawing No. 2, represent perspective views of the sternof the vessel and propeller.

Similar letters refer to similar parts throughout the several views.

A is the propeller-shaft, placed at an angle of fortyiive degrees, orthereabouts, in respect to the central line a: a: of the keel, as shownin fig. 2; and

B is the propeller, arranged to revolve in the direction of the arrows,having, in the present instance, live blades, each of which is arrangedat s uch an angle, that when at its lowest point, the face of the blade,or of the greater portion of the same, shall be at right angles to thekeel, as best observed on reference to fior. 4.

tThis arrangement of propeller was proposed by Jacob Perkins, and isillustrated in his patent of November 20, 1829. Y

In making experiments, with a view of perfecting this arrangement ofpropeller, I ascertained that it was necessary, in carrying theinvention thoroughly into effect, not only to depart, to a considerableextent, from the construction and arrangement of the propeller itself,as proposed by Perkins, but toy make the stern of the boat of peculiarshape, in order that the best effect of the propeller might 'oeobtained.

It should be understood that my propeller is not submerged, as usual.Onthe contrary, its dip in the water is very limited, as my main objecthas been to obtain a large wheel ou a vessel of very light draught.

In carrying out my invention, I have found that the best results can beobtained bythe adoption of the following features:

First, it is necessary to make in the vessel, for thev reception of thepropeller, an oblong opening, D, sit-uated at an angle in respect to thekeel, as shown in tig. 4. The portion of the vessel at the rear of thisopening should afford as little obstruction as possible to the freedisposal of the water necessarily agitated by the propeller. Hence thevessel, at this point, consists of mere platform continuation, b, of thedeck, (see fig. 3,) the under side of this platform being above thecentre of the propeller-shaft, at the rear of the same. The top of thestern-postal is securedto this platform, and its lower end is connectedto the keel by the bar e. While the platform, therefore, serves as acontinua-V tion of the deck, and as a means of securing the sternpostand carrying the rudder, the space below it is so free and open as topermit the free disposal of the water agitated by the propeller-wheel.

Sec/1nd, I have found that the eiciency of the wheel, as apropelling-medium, is increased by cutting away the vessel belowthe-water-line, at that side of the keel where the blades enter thewater. I therefore form on that side of the keel, and in the under sideof the vessel, a recess, f, figs. 4, 5, and 7, this recess being deepestat or near the corner, m, of the opening D, fig. 5,V and graduallyvanishing, in one direction, into the under side of the platform b, andin the opposite direction disappearing in a hull of the usual shape,

this being accomplished without detracting from the symmetricalappearancel of the vessel, and without weakening the overhangngplatform, as the latter obtains efcient support from the rib h on theoutside of the recess.

Third, as before observed, the dip of the blades into the water is verylimited, while the wheel itself is of large diameter'. The result ofthis, with ordinary blades, would be the striking the ,Water abruptly,the

vjarring of the vessel, and the loss of propelling-power.

In order to prevent this, I curve each blade at the edge, w, where itenters the water, as shown in fig. 4, where the line H represents thelower edge of one of the blades, as it appears when it has reached thelowest point, the remaining portion of the edge of the blade, from ttot, being straight, and at right angles to the keel. Owing to thiscurve of theblades, and

to the peculiar position of the wheel, each blade in succession will dipgently into the water before it begins to act on the saine with its fullpropelling eect.

Fourth, I have found that the best results are obtained from soarranging the shaft that it shall be higher in front than at the rear,for, by this arrangementioned curving ofthe blades adding` to thisimpork Itent result, as will be readily observed on referring to iig. 6.

\ Another advantage of lthis arrzingement of the shaft is,thaJt the rearbearing, i, een be placed on the'endor side of the platform, and thefront .bearing to the upper side of the salme, as seen in fig. 3,thereby per- -uiitting the shaft to be readily Withdrawn from itsbearings in either direction.

I claim; as my invention, and desire to seeure byr Letters Patent- 1. Arecess, f, on the under side of the vessel, et

the side of the keel, where the blades of the propeller enter thewaiter, as herein set forth, for` the purpose specified.

2. The propeller-shalt, so arranged :is to he lower at the rear than infront, in combination with an inclined propeller-wheel, having,r :tlimited dip in the water, as set forth, for the purpose specified.

In testimony. whereof, I have signed my name to this specification, inthe presence of two subscribing witnesses. y

CHRISTIAN SHARPS.

Witnesses:

E. H. BAILEY, LOUIS BosWELL.

